85578421 has 2 divisors, whose sum is σ = 85578422. Its totient is φ = 85578420.

The previous prime is 85578419. The next prime is 85578431. The reversal of 85578421 is 12487558.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 84897796 + 680625 = 9214^2 + 825^2 .

It is a cyclic number.

It is not a de Polignac number, because 85578421 - 2¹ = 85578419 is a prime.

It is a super-2 number, since 2×85578421² = 14647332281706482, which contains 22 as substring.

Together with 85578419, it forms a pair of twin primes.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (85578431) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 42789210 + 42789211.

It is an arithmetic number, because the mean of its divisors is an integer number (42789211).

Almost surely, 2^85578421 is an apocalyptic number.

It is an amenable number.

85578421 is a deficient number, since it is larger than the sum of its proper divisors (1).

85578421 is an equidigital number, since it uses as much as digits as its factorization.

85578421 is an evil number, because the sum of its binary digits is even.

The product of its digits is 89600, while the sum is 40.

The square root of 85578421 is about 9250.8605545646. The cubic root of 85578421 is about 440.6780540781.

The spelling of 85578421 in words is "eighty-five million, five hundred seventy-eight thousand, four hundred twenty-one".